The Universe's parameters have to be exactly fine-tuned to allow for the existence of life. The fact that they have been so fine-tuned argues for the existence of a Creator.
Multiverse theory is not scientific: it's a figleaf.
If you want to see an atheist’s head explode, point out that the multiverse theory implies an infinity of universes with god(s), and an infinity without ... and ask, which one do you think we live in, and why?